Pharmaceuticals bearing the 1,4-dibenzodiazepine core are a very important class of drugs. The first reported synthesis of a dibenzodiazepine (dibenzooxazepine) was clozapine and loxapine (Hunziker et al. 1964). Since this time other routes have been developed that rely on accessing them from their amide, lactam or other precursors (Lednicer 1998 and Tsvelikhovsky and Buchwald, 2011). Some important analogues with attractive medicinal properties, include the dibenzodiazepinones, sintamil for treating depression, diazepinomicin an antimicrobial alkaloid (Charan et al. 2004) and pirenzapine, an M1 selective antagonist (antimuscarinic agent), used in the treatment of peptic ulcers (Yazdanian et al. 1998). Five synthetic approaches have been developed to access dibenzodiazepinones (Li et al. 2014, one of the methods was retracted in 2014—Diao et al. 2011). Not many methods have recently been described for accessing dibenzooxazepins. The method of Buchwald and Tsvelikhovsky is particularly of note (Tsvelikhovsky and Buchwald, 2011). This method involves a Buchwald-Hartwig amination (Guram et al. 1995, Hartwig 2000, Louie and Hartwig 1995, Burke and Marques, 2015) to form the key diarylamine intermediate, followed by a Pd-catalyzed ammonia cross-coupling that terminates with a ketone condensation (Scheme 1). The reaction requires the use of 5-7 equivalents of ammonia, and the yields ranged from 43-93% for 9 examples. Only the tBu-DavePhos ligands provided satisfactory results, and it was suggested that the dimethylamino group present in the flanking ring is key to obtaining the desired reactivity (Lundgren and Stradiotto, 2012). This method constituted the first application of the Pd-Catalyzed coupling of ammonia in the synthesis of complex heterocycles. However, the reaction was carried out in two independent steps, requiring first the preparation of the diraylamine, followed by amination with ammonia and cyclization, as illustrated in the following scheme 1.

Thus, the present invention intends to provide a new efficient catalytic process which affords dibenzooxazepines in good yields.